Which of the following is a key characteristic of true experiments?

The key characteristic of true experiments is manipulation. In a true experimental design, the researcher actively manipulates one or more independent variables to observe the effect on a dependent variable. This manipulation is essential because it establishes a cause-and-effect relationship, allowing researchers to determine how changes in the independent variable influence the dependent variable.

Moreover, true experiments typically involve a control group and an experimental group, where only the experimental group receives the manipulation. This setup helps isolate the effect of the independent variable from other potential influences. Manipulation differentiates true experiments from other types of research designs, such as observational studies, where researchers do not alter any variables.

In contrast, random sampling, qualitative analysis, and subjectivity are not defining characteristics of true experiments. While random sampling can enhance the generalizability of findings in a study, it is not essential for establishing causality. Qualitative analysis focuses on understanding phenomena through non-numerical data, thus differing from the quantitative emphasis in true experiments. Subjectivity suggests personal biases influencing interpretation, which true experiments aim to minimize through controlled manipulation and objective measurement.